We will study the function and metabolism of serum albumin from several aspects. (1) Location of binding sites for physiologically important ligands such as bilirubin and long chain fatty acids, through affinity labeling and other techniques. (2) The nature of the antigenic sites on albumin, in collaboration with other laboratories. (3) The mechanism of formation of disulfide bonds during the biosynthesis of albumin in the liver. (4) The function of the aminoterminal hexapeptide on the precursor form, proalbumin, in the rat. (5) The possible presence of proalbumin in serum as an indicator of stressed production of albumin. (6) The occurrence of proteins similar to albumin in lower forms of vertebrate and invertebrate life, in an effort to learn the original purpose of albumin in evolution.